NATTERING NETWORKS THAT PROVIDE FAST FOOD FOR THE EYES

It isn`t much. And some of the ground is private and was voluntarily ceded.

But remember this about barbarians. Give them an inch and they`ll take a civilization.

These barbarians come out of Atlanta, courtesy of the Turner Broadcasting System, already guilty of desecrating several fine old motion pictures by perverting them with garish colors.

Among its wholly owned subsidiaries is CNN. Among its wholly owned subsidiaries is something called Private Networks, which is in the barbarian business.

Its purpose in life is to torment the already tormented American by subjecting him or her to even more television than he or she already endures. Well, OK, its purpose in life is to make money. But the function it performs in pursuit of that purpose is the above-described torment.

Private Network, it turns out, has been negotiating with the bigwigs of McDonald`s to provide its services to some or all of the 8,600 fast-food joints that fly the golden arches.

In other words, those waiting for their Big Mac, regular fries and medium Coke to eat here will have the opportunity to watch news and entertainment pitched just to them while they stand in line.

Oh, and perhaps also the opportunity to see commercials.

Except that ''opportunity'' is not exactly the right word. Try standing in a line under a huge screen, with its images flickering and its speakers blaring, and not paying any attention to it.

There is a simple antidote to this danger. One need not go to McDonald`s. This is a small sacrifice. In fact, the major mystery of our time may be why anyone ever enters any fast-food restaurant. So far as can be determined by an admittedly unscientific sampling, the food there is manufactured from a polypropylene-ceramic compound mixed with a woolen-rayon fabric and fried in thick pork grease. This does not include fast-food pizzas, which appear to be made entirely of cardboard. Thickly cut.

Fast-food restaurants themselves represent a major victory for the barbarians. By cheapening the public`s taste, they render people readier to accept what ought to be unacceptable.

Such as television sets blaring their drivel to innocents standing in line at the supermarket or waiting at the gate area for their (delayed, no doubt) flight.

Which, in its iniquity, Private Networks is already inflicting upon some of our fellow citizens. The Check Out Channel is operating in 15 markets, and the Airport Channel (how much do you figure they paid the guy who dreamed up those names? Too much.) has been tested at six airports.

Where will it all end? Will there be no place to get away from some blow-dried geek reading you the ball scores and urging you to switch brokerage houses? Airports and supermarkets are unpleasant enough as it is, in part because they are filled with too many ugly noises. Adding yet another is not a step in the right direction.

It is possible that free enterprise will provide some salvation. So that if McDonald`s gets its own private channel, Wendy`s or Burger King could advertise-''come to us and eat your polypropylene-ceramic-wool en-rayon in peace and quiet.'' Or, if American Airlines puts the Airport Channel at its gates, United could say, ''fly our friendly and relatively less obtrusive skies.''

Alas, on recent form none of this is likely. Have you ever been the only customer in a hotel or airport bar at night with the television blaring and asked the bartender to turn it off, or at least down? Chances are he or she replied that such a move would be against the rules. The boss, perhaps somebody the bartender has never met, the bar being part of a national chain headquartered far away, has decreed that at all times the television will be turned on, with channel and volume preset, and the customers go hang.

There is but one explanation for this, and also for the Private Network company. Market survey research has concluded that the average American cannot bear even one moment without being entertained-well, diverted. This explains why so many people can`t go anywhere without their headset and/or boom box. It also explains the comment of Turner Private Networks executive vice president Scott Weiss to the Tribune`s Nancy Ryan: ''The No. 1 customer complaint is

(about) waiting. A five-minute wait is perceived by a customer as being a 15-minute wait. This provides productive use of people`s time.''

Forget for a moment that this man needs a crash course in the meaning of the word ''productive.'' There are two possibilities. One is that the market survey research has underestimated the public and is wrong; the other is that it is right and that we have become a people whose minds, themselves unfilled, cannot bear an unfilled moment.